TY175 Rings

[TriCub]

The Ebay piston is cheap enough, as David said measure it carefully. I've tried to fit a cheap Chinese piston to an RM125 a few years ago that the owner had supplied and it was machined that badly that the rings jammed into the grooves and on the second kick trying to start for the first time, it lost compression and wouldn't even run but it was cheap!
You have ordered it so give it a try but don't through away your Yamaha piston as it may work better than the new one.
Piston coating? I assume you are talking about Ceramic coating the crown and teflon coating the skirt. Don't believe the claims they make about that stuff it only makes a marginal difference in a motor like yours.
Wossner make pistons for the 175's that come with a black coating on the skirt if your set on a coated piston. Your local shop could get you one or you can go direct to Serco in Brisbane or Bikes & Bits in Perth. Bikes & Bits are wholesale only I think so they will only supply to shops.
Good luck with it and enjoy

[jacks1071]

If/When a rebore is necessary I'll send the barrel away for nikisil coating along with a replacement piston & rings and they'll match it up.

David - can you show me the link to the genuine L-shape rings or do you know the part number I need for STD size? I did see some on the net but I couldn't work out from the picture if they were the L Shape or not so I ordered the whole lot with the after-market piston to ensure it would fit.

We will check the gap and all that before assembly - if its still out of spec then we'll re-bore or get the nikisil done..

The genuine piston barely has any marks on it so would be fine to re-use if we can find the right rings.

We still have the 1st set of rings that came out of Dad's TY back in the early 1980's and they were not the L-shape type and the gap on them was worse than the rings that have come out of the current bike, they must have moved away from the L-shape rings at some point? Dad's TY175 I think was the last model made, about 1979.

[TriCub]

I've never seen a cast iron bore that was nikisil plated, as far as I know it is only done onto Aluminium. So to nikisil a TY175 barrel you would have to get all the cast iron bored out then have an aluminium sleeve made to take it back to standard bore before getting nikisiled. Could be a little expensive!

I gave our local Yamaha dealer a ring and the part number is 443-11610-00 . The parts are no longer avaliable but they gave me the number of a couple of dealers that still have them listed. I had a quick on Evil bay and could only see oversize ring sets at the moment.
Inverell Motorcycles 02 67211200
Les Penna Motorcycles 03 54435375
There were more if they couldn't help.

[jacks1071]

I've never seen a cast iron bore that was nikisil plated, as far as I know it is only done onto Aluminium. So to nikisil a TY175 barrel you would have to get all the cast iron bored out then have an aluminium sleeve made to take it back to standard bore before getting nikisiled. Could be a little expensive!

I gave our local Yamaha dealer a ring and the part number is 443-11610-00 . The parts are no longer avaliable but they gave me the number of a couple of dealers that still have them listed. I had a quick on Evil bay and could only see oversize ring sets at the moment.
Inverell Motorcycles 02 67211200
Les Penna Motorcycles 03 54435375
There were more if they couldn't help.

I'm not positive but I am fairly sure they can plate a cast iron bore. Will try and chase up the rings, thanks for the part#

[FM350]

BMW cars used to have Nikasil plating on cast iron cylinder blocks. Failure was quite common, and they gave up the idea.

[Stork955]

Gday, and further to the above, you will be lucky if you can get chrome rings to run in the nikasil bore. Cast rings will last anything up to about 15 minutes.
Don't Nikasil this bike.
Cheers,

Stork

[jacks1071]

Gday, and further to the above, you will be lucky if you can get chrome rings to run in the nikasil bore. Cast rings will last anything up to about 15 minutes.
Don't Nikasil this bike.
Cheers,

Stork

Hmm might have to give up on the Nikasil from the sounds of it

I've found two sets of NOS rings so looks like the origional piston is going back in and the ebay one will become a spare. Hopefully it measures up alright but I am pretty confident the bore is fine and won't need to be over-sized.

Thanks to all for your help and advice!

[FM350]

Rings today are made from either nodular iron (which are OE in Fantic and work perfectly), or plated steel, which in the case of Wisceo pistons are made by NTN in Japan and will run in Nikasil or cast iron cylinder liners.

You can get a pretty accurate idea of cylinder wear by measuring the piston ring end gap with the ring at top, middle, and bottom of the liner, using the piston to make sure the ring is square to the cylinder. If there is anything more than a few thou difference you will need a rebore, and on the 175cc motors setting the bore clearance to 1.5thou will greatly reduce the chances of a rattly top end.

[TriCub]

Gday, and further to the above, you will be lucky if you can get chrome rings to run in the nikasil bore. Cast rings will last anything up to about 15 minutes.
Don't Nikasil this bike.
Cheers,

Stork

Hmm might have to give up on the Nikasil from the sounds of it

I've found two sets of NOS rings so looks like the origional piston is going back in and the ebay one will become a spare. Hopefully it measures up alright but I am pretty confident the bore is fine and won't need to be over-sized.

Thanks to all for your help and advice!

The new rings should keep you going for a while.
You got me curious regarding that nikisil on cast iron, thought I was going to have to trade in my boring and honing equipment on a plating bath. I did a bit of research by contacting one of the Ausy places that do it and it's a definate no on cast iron as the cleaning procedure required before plating eats iron and also the cast iron after use in a barrel has to much carbon and oil impregnated in it for the process to work. It may be possible to have it hard chrome plated but the same applies with the impurities in that process as well and the risk of it peeling of would be quite high. Also you would have to use ductile iron rings on the chrome which could be hard to find.
Forget about plating but the coatings I mentioned before on the piston will increase the engine life to a degree. The ceramic on top of the piston reduces the heat tranfer from combustion into the piston and the teflon on the skirt makes for less friction which all adds up to longer life. If you believe all the claims that is what is meant to happen but the question is whether the cost of doing it outweighs the extra life it gives.

Enjoy your new rings.

[jacks1071]

For those interested, we fitted the new rings and the standard bore is still within spec. Just waiting on tyres now so we can use it.